| Explore | What we know about plants from our experiences outside of school is that they need water and sunlight to grow. They use photosynthesis to create sugars that they use as food. The inputs of photosynthesis are sunlight and carbon dioxide (CO₂ ), meaning without the energy from the sun or carbon dioxide from the air plants won't be able to grow and gain mass. Questions about plants that interest us are what effects does a plant receive when given different amounts of CO₂ and what will happen to a plant if it did not get energy from the sun. |
|---|---|
| Research Question | In our experiment we wanted to see how large amounts of carbon dioxide (CO₂) affect photosynthesis. We came up with this idea after we had seen that when a plant is give more CO₂ than the air around it the plant would have a higher rate of photosynthesis. This then caused us to ask the question of what would the effects would be of other amounts of CO₂. |
| Predictions | Our group predicted that the large amounts of carbon dioxide (CO₂) would slow down photosynthesis as it's getting too much of the materials that are used in photosynthesis and suffocate on the excess amount. |
| Experimental Design | Our plan was to see the effects of different amounts of carbon dioxide (CO₂) on leaf disks. We had three cups with different amounts of baking soda, the first one was with 5% baking soda, second was with 1%, and the third had .2%. We cut out 36 spinach leaf disks and put 12 leaf disks in three different syringes to vacuum out the air molecules in the spaces so water can fill it up instead of air. After all the leaf disks sunk, we poured the different syringes with the three different solutions, and scooped out the leaf disks that were floating. Then we put all three cups under light and recorded the results of which leaf disks were floating and which were not after every 5 mins for 30 mins, and made a chart and line graph for the results at the end. |
| Conclusion | After completing our experiment we found that when a spinach plant receives high amounts of carbon dioxide (CO₂) the process of photosynthesis was slowed as the cup with the most CO₂ produced less results than the other two cups that were tested. We collected the data based upon the amount of leaf disks that floated to the surfaces in the cups with different amounts of CO₂ content over a period of 30 minutes with us recording every 5 minutes (until the 20 minute mark where we proceeded to record every 2 minutes, then every minute when reaching 27 minutes.) Our group figured that the leaf disks rising to the surface showing photosynthesis occurred in the leaf disks as the oxygen would have caused them to float. The outcome to out experiment could have been due to an error that occurred when preparing the experiment. When we tried to remove the air from the leaf disks for the cup with the most CO₂ it took a few tries to vacuum out the leaves which could have damaged the leaf disks' interior, causing a problem in the process of photosynthesis. Other experiments that could be done to further the research would be trying different types of plants as well as different amounts of CO₂ given. |
| Investigation Theme | POS |
| Grade Level | High School Students (Grades 9,10,11,12) |
| School Name | Arthur L. Johnson High School |
| Session | Fall 2017 |